Bituminous emulsions for treatment of coal and methods of preparing same



Patented July 1 1, 1 950 I BITUMINOUS EMULSIONS FoR TREATMENT oEcoAL ANDMETHODS OF PREPARING I SAME Charles R. Rosencranse, Pittsburg, Kans.,assignor of fifty per cent to Joe F. Klaner, J1'., Pittsburg,

a Kans.

i i No. Drawing.

This invention relates to. a colloidal suspension to be sprayed on coalto form a permanent coating rendering the coal substantially dust-proofand impervious to moisture and oxidation, the present subject matterinvolving an improvement over the subject matter in my Patent No-2,431,89L'issued December 2, 1947.

An imp'ortantobject'of this invention is to provide acolloidalsuspension which does not require the application of heat whenit is sprayed or coated on coal, andwhich while forming a hard, dry, andpermanent coating on the coal, does not cause the coalparticles toobjectionably adher togethen;

Another important object of the invention is I to provide a bituminousemulsion for coating coal may come into contact.

By coal as referred to herein, is meant bituminous, semi-bituminous,anthracite, semiobjects or materials; with which the coated coalanthracite, or the so-called lignite. coals, and

others comprehended by these terms.

After extensive experimentation with the process and compositiondisclosed in the patent mentioned' hereinabove, I have discovered that anumber of improvements could be made wherein the'resulting emulsionproduces a better sheen and color on the. coal treated, affords betterprotection to the coal, and produces an odorless coating for the coal.

The primary improvement resides in the substitution of coal tar pitchfor the asphalt,.arti'- ficial or natural, employed in the patentedprocess. As is well known in the art, coal tar pitch is the residue fromthe distillation of coal tar from which the aromatic substances havebeen removed." Coal tar pitch is a solid substance of varying'degrees ofhardness whichis determined by the amount of distillation used to removethe aromatic substances. In the dry state it has an approximate specificgravity of 1.20. ,7

Since coal tar pitfchisless soluble than asphalt, obviously coal coatedwithcoal tar pitch willbe better protected against moisture andoxidation. ".elsogcoal coated with coal tar pitch is relativelyApplication November 17, 1948, Serial No. 60,634

j v a I SClainisJ, (c1. iota-277) odorless as compared to coal coatedwith asphalt emulsion. To the best of the applicant's knowledge, coaltar pitch has never before been successfully employedin manufacturing anemulsion for the treatment of coal because of the acidity of the pitch.The herein described improved process and composition includes a novelmethod of reducing this objectionable acidity.

In the patented process before the asphalt is run through the colloidmill for admixture with the aqueous dispersion, it was found necessaryto use an asphalt having an initial penetration of 8 to 10 mm. andpreferably a ductility rating of about 15 to 18 mm. and then blowing theasphalt at an oxidizing temperature inan oxidizing chamber with about4,000 cubic'feet of air per minute for a length of time necessary toreduce the penetration of the asphalt to about 2.6 to 3.0 mm.

thereby raising the melting'point' of the asphalt to about 210 to 260degrees F. While the same treatment can be applied to coal tar pitchwith advantageous results, it has been found herein that no suchtreatment is required when a coal F. is employed.

In the patented, process it was also necessary to simultaneously run theheated and treated asphalt together with the heated aqueous dispersionthrough a colloid mill operating at substantially 5,000 B. P. M. and ata constant rate. A marked advantage is obtainedby running the colloidmillat approximately half its normal rate of speed.

It has been found that by reducing the amount of material entering thecolloid mill instead of reducing the speed of thev mill itself, a markedimprovement of the resulting emulsion is obtained with respect to thestability of the emulsion. In other words, rather than reduce the speedof the colloid mill by one' half, the material is fed into the mill at arate equal approximately to onehalf of the flow or output capacity ofthe mill. .In the patented process, also, an aqueous dispersion wasemployed containing a number of essential ingredients.

The applicant has found that a variation ofthe percentages by weight ofthese ingredients produces a dispersion which allows thesubstitution'of'coal tar pitch for asphalt and which also permits him todispense with the blowing' orpre-treatment of both the asphalt and thecoal tar pitch.

f Moreover, theapplicant has found that a prior mixture. in a ;mixingchamber of the heated asphalt and coal tar-pitch with the aqueous disthepreferred embodimentbeing coalutarwpitch.

When employing asphalt, a material having a penetration of 2.6 mm.ispreferred and if an asphalt having a higher penetration is employed itwill be found advantageous to reduce the penetration and raise themelting point thereof by the oxidation and blowing treatment fully de Ifa coal tar scribed in the patented process. pitch having a penetrationof from 26to 30 .mm. and a melting point of from 190 to 210 degrees F.is employed, no pre-treatmentsuch asblowing or oxidation is required Thecoal tar pitch is then heatedin a container until it is fluid, that is,to atemperature not exceeding 300 degrees F., and then runpreferablyinto a mixing chamber where it is mixed with preferably an equalvolumeof anaqueous dispersion to be described hereinafter. Thereafter theadmixture or suspension of the pitchand the dispersion is runinto .acolloid mill at a velocity equal approximately to one-half of .the flowcapacity of the colloid mill. That is, if the capacity of the colloid.milll'is 4,000 gallons per hour, the speedof the pumps whichintroduoethe suspension intothe mill i'slreduced so that the mill can onlyproduce 2,000 gallons .per hour.

The liquid phase of the emuls'ionor what may be termed the aqueousdispersion-comprises the following ingredients:

Water 93.74-95.04 Resin 3.00 Bentonite clay 1.40 1.60 Tall oil s 0.10

Caustic soda Per cent by Weight Water 93.74 Resin 3.00 'Bentonite clay1.60 Tall oil 0.10 Caustic soda 1.56

It will be noted that the dispersion-mentioned immediately hereinabovediffers from the onedisclosed in the Patent 2,431,89lin that the amountof bentonite clay and caustic soda is increased. The increased bentonitecontent improves the stability of the emulsion and the increased amountof caustic soda neutralizes the acidity inthe coal tar pitch, whichacidity was responsible for the prior inabilityofproviding a stable Percent by weight r emulsion from bituminouslmaterial such as coal tarpitch.

It has also been found that a prior treatment of the coal tar pitch whenheated to a state of fluidity before admixture with the aqueous.dispersion improves the stability of the emulsion and the coatingproperties thereof. This prior treatment includes the addition of a weaksolution of caustic soda in glycerine to the fluid coal tar pitch. Thepreferred amount of caustic soda to be added to the coal tar pitch is0.44% by "weight 'of' the-caustic soda to the weight of the coal tarpitch. This solution of caustic soda and glyoerine is, of course,thoroughly mixed throughout the fluid coal tar pitch phase.

Thus it will be seen that a novel process and composition is providedfor coating coal whereby the latter will be rendered impervious tomoisture; oxidation, etc. The coating material of the present invention,requiring no heating above its freezing point, can be sprayed oratomized on the coal, directly from the storage containers, and

by -means of any suitablesprayin'g equipment. The bituminous emulsionprovided by the improved-process hereinabove described produces abetterv sheen and'color on the coal, affords better protection tothecoalilbecause of the lesser solubility of coaltarpitchas compared toasphalt, andproduces a relativelyodorless coating for the coal.

While a preferred embodiment of the applicanrs process and compositionhas been described hereinafter, itwill bereadily understood that minorvariations in 'the process and composition may be made by thoseskilledfin the art without departing from the spirit .of the-inventionand the scope of the appended-claims.

Having described the invention, what is claimed asnew is:

1. The method of vmaking a collo'idal suspension for spraying on coal'atatmospheric temperature to form a permanent coating rendering the coalsubstantially dust-proof and-impervious to moisture and oxidation,comprising heating coal tar pitch having apenetration of 2.6-. to 30.0mm. and amelting point-05190 to 260 F. to a temperature not over 300 F.,running the heated coal 1 tar.pitch through a mixing chamber togetherwith an aqueous -dispersion heated to about 180 .thenisimultaneouslyrunning the suspension through a colloid mill at a velocity equalapproximately to one-half of the'fiow capacity of themill, saiddispersion comprising by weight substantially 93.7.4-95.04% .water,3.00% of a substantially'petroleumlhydrocarbon insoluble pine. woodresin, l 40-1.60% bentonite, 0.10% tall oil, and DAG-1.56% causticsoda,- then rapidly reducing the resultant emulsion-to a tem perature of150-F, for storage.

'2. The process-of claim 1, and the step of adding to the heated coaltar pitch prior .to admixture with the dispersion a relativelyweaksolution of caustic soda Zin-glycerine.

v3. The processof claim 2, wherein the caustic soda is. added inan-amount equal lie-0.44% by Weight of the coal tar pitch.

4. The method of making .a colloidal-suspension .for spraying on coal atatmospheric temperature to form a permanent coating rendering the coalsubstantially dust-proof and impervious to moisture and oxidation,comprising heating to a temperature not over 300- F.', coal tarpitchhaving a penetration of 26-30' mm. and a melting point of 190-2l0F.,,running the, heated vpitch through a mixing. chamber together withan simultaneously running the sus ension through a ture with thedispersion a relatively weak solution of caustic soda in glycerine.

6. The process of claim 5, wherein the caustic soda is added in anamount equal to 0.44% by weight of the coal tar pitch.

7. The method of making a colloidal suspension for spraying on coal atatmospheric tem-- perature to form a permanent coating rendering thecoal substantially dust-proof and impervious to moisture and oxidation,comprising heating to a temperature not over 300 F., coal tar pitchhaving a penetration of 26-30 mm. and a melting point of 190-210 F.,simultaneously running the heated pitch through a colloid mill togetherwith an aqueous dispersion heated to ,about 180 F., said dispersioncontaining by weight substantially 95.04% of water, 3% of asubstantially petroleum hydrocarbon insoluble pine wood resin, 1.4% ofbentonite, 0.10% of tall oil, and

' 0.46% of caustic soda, then rapidly reducing the temperature of theresultant emulsion-to about F., for storage. 8. A colloidal suspensionfor spraying on coal at atmospheric temperature to form a permanentcoating rendering the coal substantially dust-proof and impervious tomoisture and ox-i dation, comprising coal tar pitch having a penetration of 26-30 mm. and a melting point of 190-210 F, which has beensimultaneously run through a colloid mill together with anaqueousdispersion heated to about F.- at a velocity equal approximatelytoone-half oi the flow ca pacity of the mill, said dispersion comprisingby weight substantially 93.74% water, 300% of a substantially petroleumhydrocarbon insoluble pine wood resin, 1.60% bentonite, 0.10% tall oil,and 1.56% caustic soda.

CHARLES R. ROSENCRANSE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,807,808 Symons June 2, 19312,190,034 Levin Feb. 13, 1940 2,431,891 Rosencranse Dec. 2, 1947 FOREIGNPATENTS Number Country Date 462,111 Great Britain Mar. 2, 1937

1. THE METHOD OF MAKING A COLLOIDAL SUSPENSION FOR SPRAYING ON COAL ATATMOSPHERIC TEMPERATURE TO FORM A PERMANENT COATING RENDERING THE COALSUBSTANTIALLY DUST-PROOF AND IMPERVOUS TO MOISTURE AND OXIDATION,COMPRISING HEATING COAL TAR PITCH HAVING A PENETRATION OF 2.6 TO 30.0MM. AND MELTING POINT OF 190* TO 260*F. TO A TEMPERATURE NOT OVER300*F., RUNNING THE HEATED COAL TAR PITCH THROUGH A MIXING CHAMBERTOGETHER WITH AN AQUEOUS DISPERSION HEATED TO ABOUT 180*F., THENSIMULTANEOUSLY RUNNING THE SUSPENSION THROUGH A COLLOID MILL AT AVELOCITY EQUAL APPROXIMATELY TO ONE-HALF OF THE FLOW CAPACITY OF THEMILL, SAID DISPERSION COMPRISING BY WEIGHT SUBSTANTIALLY 93.74-95.04%WATER, 3.00% OF A SUBSTANTIALLY PETROLEUM HYDROCARBON INSOLUBLE PINEWOOD RESIN, 1.40-1.60% BENTONITE, 0.10% TALL OIL, AND 0.46-1.56% CAUSTICSODA, THEN RAPIDLY REDUCING THE RESULTANT EMULSION TO A TEMPERATURE OF150*F. FOR STORAGE.